Active thermal switches operate between states of thermal conductivity during which the switch transfers heat, and thermal insulation during which the switch conducts less or negligible heat. Miniaturized and/or arrayed active thermal switches could enable a range of new applications, including improving thermal management of integrated circuits and chip packages and new energy concepts. Current approaches have been unable to achieve distinct thermal contrast between the high heat conducting state and the low heat conducting state with small form-factors and fast actuation at temperatures suitable for many energy harvesting or cooling applications.
Issues may arise with thermal switches and their thermal conductivity contrast, switching speed, and the ease or difficulty of construction. Thermal conductivity contrast means the ratio of the thermal conductivity with the switch on to the thermal conductivity with the switch off. Many current approaches do not have good contrast. Similarly, many approaches have slow switching speeds between the thermal switch being on and off. Finally, many thermal switches have very complicated manufacturing processes, and use materials that can be difficult to handle or materials that are expensive. It becomes difficult to manufacture current heat switches efficiently and even more difficult to manufacture them in arrays.